1. Field of the Invention
This invention relates to a biochemical analysis method and apparatus, wherein a sample, such as blood or urine, is spotted onto a dry chemical analysis element, such as a colorimetric-type dry chemical analysis element or an electrolyte-type dry chemical analysis element, by use of a spotting unit, and a substance concentration of a specific biochemical substance contained in the sample, an ionic activity of a specific ion contained in the sample, or the like, is determined. This invention also relates to a dry chemical analysis element for biochemical analysis and particularly to a technique for imparting analysis information, and the like, to the dry chemical analysis element.
2. Description of the Related Art
Colorimetric-type dry chemical analysis elements and electrolyte-type dry chemical analysis elements have heretofore been used in practice. When a droplet of a sample is merely spotted onto the colorimetric-type dry chemical analysis element, a specific chemical constituent or a specific physical constituent contained the sample is capable of being analyzed quantitatively. Also, when a droplet of a sample is merely spotted on to the electrolyte-type dry chemical analysis element, an ionic activity of a specific ion contained the sample is capable of being analyzed quantitatively. Biochemical analysis apparatuses utilizing the dry chemical analysis elements are capable of performing sample analyses easily and quickly and have therefore been utilized widely in medical facilities, medical laboratories, and the like.
Colorimetry utilizing colorimetric-type dry chemical analysis elements is performed in the manner described below. Specifically, after a sample has been spotted onto a dry chemical analysis element, the dry chemical analysis element having been spotted with the sample is kept at a constant temperature for a predetermined time within an incubator and is thereby caused to undergo a color reaction (i.e., a dye forming reaction). Thereafter, measuring light, which has wavelengths selected previously in accordance with a combination of a predetermined biochemical substance contained in the sample and a reagent contained in the dry chemical analysis element, is irradiated to the dry chemical analysis element, and an optical density of the dry chemical analysis element is thereby measured. The concentration of the predetermined biochemical substance contained in the sample is determined from the measured optical density and by use of a calibration curve having been formed previously, which represents a correspondence relationship between the optical density and the substance concentration of the predetermined biochemical substance.
Potentiometry utilizing electrolyte-type dry chemical analysis elements is performed in the manner described below. Specifically, in lieu of the optical density described above being measured, the ionic activity of a specific ion contained in a sample, which has been spotted onto an electrode pair comprising a pair of two dry type ion selective electrodes of an identical type, is determined through quantitative analysis with potentiometry by use of a reference liquid.
In each of the colorimetry and the potentiometry described above, the liquid-state sample is accommodated in a sample vessel (such as a blood-collecting tube), and the sample vessel accommodating the sample is set on a biochemical analysis apparatus. Also, the dry chemical analysis element necessary for the measurement is loaded into the biochemical analysis apparatus. Further, the dry chemical analysis element is conveyed from a position for element loading into a spotting section and into an incubator. Furthermore, the sample is fed by a spotting nozzle from a position for sample loading to the spotting section and spotted onto the dry chemical analysis element.
The kind of the dry chemical analysis element and the technique for the sample spotting onto the dry chemical analysis element vary in accordance with the type of the analysis. Therefore, each of the dry chemical analysis elements utilized for the analyses is appended with analysis information, which contains information representing the type of the analysis, by use of a bar code recording technique, or the like. Also, in cases where the dry chemical analysis element is loaded onto a sample tray of a biochemical analysis apparatus directly or by use of a cartridge, the biochemical analysis apparatus is controlled such that the dry chemical analysis element is taken out from the sample tray, the analysis information is read from the dry chemical analysis element, and an operation for sucking a sample, which corresponds to the type of the analysis to be made with the dry chemical analysis element, is performed in accordance with the analysis information having been read from the dry chemical analysis element.
Also, ordinarily, a plurality of types of analyses are performed with respect to one sample. Therefore, there have heretofore been proposed biochemical analysis apparatuses, in which a plurality of kinds of dry chemical analysis elements are loaded in a laid-up state on a sample tray in accordance with each sample, and analyses are performed successively by use of the dry chemical analysis elements. In such cases, in order for the one sample to be successively spotted onto the plurality of the kinds of the dry chemical analysis elements, it is necessary that the operation for reading the analysis information and the operation for sucking the sample are iterated with respect to each of the dry chemical analysis elements.
Ordinarily, the operation for reading the analysis information, which has been appended to the dry chemical analysis element, from the dry chemical analysis element is performed in the manner described below. Specifically, information reading means is located at an intermediate point of an element conveyance path, along which the dry chemical analysis element having been taken out from the sample tray, is conveyed to the position for sample spotting. Also, the operation for reading the analysis information is performed in accordance with the operation for conveying the dry chemical analysis element.
However, with the aforesaid technique for reading the analysis information from the dry chemical analysis element, if the dry chemical analysis element having been taken out from the sample tray onto the element conveyance path is conveyed in a state in which the front surface and the back surface of the dry chemical analysis element are reversed or in a state in which the orientation of the dry chemical analysis element is incorrect, the problems will occur in that the analysis cannot be made accurately, and the analysis information cannot be read from the dry chemical analysis element. In such cases, warning, or the like, is given by the reading means. However, in such cases, the dry chemical analysis element, which has already been sent onto the element conveyance path must be taken out from the element conveyance path, the conveyance of the dry chemical analysis element must then performed again, and the operation for reading the analysis information from the dry chemical analysis element must again be performed. Therefore, a considerable time and labor are required, and the processing efficiency cannot be kept high. Also, in cases where, for example, the biochemical analysis apparatus comes short of expendables, or the sample and the dry chemical analysis element do not conform to each other, after the analysis operation has been started, a necessary correcting operation must be performed, and the analysis operation must then be performed again. In such cases, a considerable time and labor are required.
In order for the problems described above to be solved, it may be considered that the operation for reading the analysis information from the dry chemical analysis element is performed in the state, in which the dry chemical analysis element is loaded on the sample tray, and before the conveyance of the dry chemical analysis element is started. However, in such cases, it becomes necessary, depending upon the position at which the reading means is located, that the sample tray is moved to the position for information reading, then moved to the position for element takeout, and thereafter moved to the position for sample suction. Therefore, the problems occur in that control of the operation of the sample tray and sequence control cannot be kept simple, a considerable time is required to perform the processing, and the analyses cannot be performed quickly.